Actor Paul Walker attends the film premiere of "Timeline" at the Mann's National Theatre on November 19, 2003 in Westwood, California. The film "Timeline" was released on November 26, 2003. (Photo by Frederick M. Brown/Getty Images) (Frederick M. Brown)

Actor Paul Walker died of a combination of multiple traumatic and thermal injuries, the Los Angeles County Coroner's office said Wednesday.

The office also officially confirmed the identities of Walker, 40, and 38-year-old financial manager and part-time race car driver Roger Rodas, who was behind the wheel of a 2005 Porsche Carrera GT when it crashed an exploded in Valencia Saturday, killing both men.

Rodas died of multiple traumatic injuries, according to the preliminary autopsy. The office also confirmed that Rodas was driving and Walker was a passenger in the car, something that was widely believed but not officially confirmed prior to the autopsy.

The final autopsy report will be completed in six to eight weeks, when toxicology results are ready.

The two men took the car out for a ride during a charity event at Always Evolving performance auto shop. Rodas apparently lost control of the vehicle and knocked over a light pole and hit a tree before the car burst into flames.

Los Angeles County firefighters and a number of attendees from the event responded to the fire, but were unable to rescue either man. Both were declared dead that the scene.

Sheriff's investigators are still trying to determine the cause of the crash, but have said that speed was a factor. Witnesses have said the car was traveling much faster than the posted 45 mph speed limit just prior to the crash.

Detectives have also ruled out a number of early theories for the cause of the crash, including the possibility that the pair were involved in a street race or that there was a fluid leak from the car.

The car the two men were in is also notoriously difficult to handle, and several experienced race car drivers have reported stability problems in the Carrera GT, which has a V-10, 610-horsepower engine. The supercar has been involved in at least one wrongful death lawsuit that alleged the vehicle has a design defect that caused poor handling and is too difficult to handle at high speeds for the average driver.

First responders gather evidence near the wreckage of a Porsche sports car that crashed into a light pole on Hercules Street near Kelly Johnson Parkway in Valencia on Saturday, Nov. 30, 2013. A publicist for actor Paul Walker says the star of the "Fast & Furious" movie series has died in a car crash north of Los Angeles. He was 40. Ame Van Iden says Walker died Saturday afternoon. No further details were released. (AP Photo/The Santa Clarita Valley Signal, Dan Watson) (Dan Watson)

In 2005, two men were killed at California Speedway when the driver swerved to avoid another car, lost control and slammed into a retaining wall at 130 mph. In that lawsuit, Porsche settled with the widow of the car's passenger, and paid $360,000 of the total $4.5 million settlement.

A fan memorial at the site of the collision, near Hercules Street and Kelly Johnson Parkway, has continued to grow in the days since the accident.

There have been no announcements regarding funeral services for Walker or Rodas, but a fan memorial is planned for Sunday at the crash site.

Walker was on a Thanksgiving break from filming “Fast and Furious 7” at the time of his death. Universal Pictures said Wednesday that production of the movie is being halted.

“Right now, all of us at Universal are dedicated to providing support to Paul's immediate family and our extended Fast & Furious family of cast, crew and filmmakers,” a studio rep announced today in a statement. “At this time we feel it is our responsibility to shut down production on Fast & Furious 7 for a period of time so we can assess all options available to move forward with the franchise.”